Presentation on theme: "Alignment of DB and MB quadrupoles Hélène MAINAUD DURAND 17/11/2011 With a lot of input from Sylvain GRIFFET."— Presentation transcript:
Alignment of DB and MB quadrupoles Hélène MAINAUD DURAND 17/11/2011 With a lot of input from Sylvain GRIFFET
Outline Actual plan Case of MB quad and DB quad Means Proposals and questions
3 Main linac alignment requirements Problem Within +/- 0.1 mm (1 ) Active pre-alignment Beam based alignment Beam based feedbacks Within a few microns Active pre-alignment = Determination of the position of the components in a general coordinate system thanks to alignment systems Re-adjustment thanks to actuators + The zero of each component will be included in a cylinder with a radius of a few microns: 14 μm / 17 μm for main linac components 1 µm Adjustment required: step size below 1 µm, 5 DOF Mechanical pre-alignment PRE-ALIGNMENT (beam off)
5 Alignment strategy Solution proposed (for all area of CLIC) Installation and determination of the Survey network Transfer of reference into tunnel Installation and determination of the tunnel network Combination of 3D triangulation and trilateration coupled with measurements of on vertical plumb wires Methods validated on an LHC pit in 2010 (depth of 65 m): precision of 0.1 mm and accuracy of 0.5 mm Hypothesis considered for CLIC: absolute position at the bottom of each pit: ± 2 mm (depth > 100 m) Distance < 2.5 km
6 BDS: strategy Solution proposed Absolute alignment of the elements Relative alignment of the elements Metrological Reference Network Installed w.r.t the tunnel network Overlapping stretched wires propagating the precision over long distances Simulations in 2009: o Precision at the bottom of the shaft of ± 2 mm o Calibration of metrological plates: ± 5 μm o Distance between pits: 3.5 km o Wires: 400m long Std deviation of 3.6 μm over 200m of sliding window Propagation network simulations
7 Alignment strategy Solution proposed Absolute alignment of the elements Relative alignment of the elements All the components or the supports on which are pre-aligned the components will be aligned w.r.t Metrological Reference Network (overlapping stretched wires) All the components must be pre-aligned on their supports within a micrometric precision and accuracy As the requirements of alignment concern the zero of each component, the position of each zero of component must be known within a micrometric precision and accuracy w.r.t the sensor interface. Laser tracker: AT 401 cWPS mechanical interface
8 Alignment strategy Summary of the configuration
9 Alignment strategy Summary of the fiducialisation steps for DB quad: Determination of each zero of component w.r.t fiducials (external alignment references): BPM, DB quad Assembly and measurement of the assembly of components w.r.t their fiducials (DB quad and BPM) Alignment of components on supports (DB quad + BPM on girders) and determination of their position in the support coordinate system Determination of the supports coordinate system w.r.t sensors interface Best solution for accuracy : to group the determination of the zero of the components w.r.t sensors interface! Zero of component to be precised.
10 Alignment strategy Summary of the fiducialisation steps for MB quad: Determination of each zero of component w.r.t fiducials (external alignment references): BPM, MB quad Assembly and measurement of the assembly of components w.r.t their fiducials (MB quad and BPM) Alignment of components on supports (MB quad + BPM on common support) and determination of their position in the support coordinate system, for a given position of micro positioning adjustment system (stabilization) Determination of the supports coordinate system w.r.t sensors interface Best solution for accuracy : to group the determination of the zero of the components w.r.t sensors interface!
11 Alignment strategy 2 solutions concerning the location of sensors: Sensors directly on the components Lever arm effect towards alignment reference (stretched wire) important Heavy load on BPM Sensors mounted on the common support: The position of micro positioning adjustment system must be taken into account Determination of the position of BPM not direct
15 Means and strategy Fiducialisation and dimensional control of objects < 1.2 m: CMM measurements (Tolerances of measurement of Leitz Infinity: 0.3 μm + 1 ppm) For objects > 1.2 m or as control after transport: Combination of « mobile » means: Laser tracker: AT 401 Micro triangulation InstrumentStandard deviation between instruments and CMM measurements AT401< 5 μm Micro triangulation < 5 μm Romer arm< 10 μm Romer arm
16 Some ideas… Objective: the most precise and accurate measurement between the zero of the component and the sensors interfaces. Perform the measurement of the magnetic axis of DB quad and MB quad in a CMM If a “vibrating stretched wire” technique is used to perform the magnetic measurements, measure the position of this wire thanks to oWPS and cWPS. Then their mechanical interfaces and the mechanical interfaces of the alignment sensors can be determined through very accurate CMM measurements. For the DB quad, use WPS mounted on supports installed on the V-shaped supports.
17 Some questions… Definition of the zero of the components Case of the MB quad: according to the requirements, the position of BPM should be known more precisely and accurately than the MB quad: 2 configurations to be studied Clear definition of the tolerances needed: what does “quadrupole offsets: 20 µm” mean? Kinematic pitch problem raised by Kurt: For the type 1: for a pitch with vertical delta of 1 mm, φ=0.38° - longitudinal displacement of the center of ~ 2.5 mm - vertical displacement ~ 8 µm